Should We Be Searching for Dinosaur Vomit?

Numerous extant carnivorous, piscivorous and insectivorous species – including birds, pinnipeds, varanid lizards and crocodiles and mammals – routinely ingest food combined with a high proportion of indigestible material that can be neither absorbed through digestion nor eliminated as faecal matter. Their solution is to egest the indigestible portion through the mouth as a gastric pellet. The status of gastric pellets in extant species is reviewed. Arguments based on phylogeny, anatomy and biomechanics strongly suggest that many extinct species, including crocodilians and pterosaurs, may also have produced gastric pellets routinely. The term ‘emetolite’ is proposed for fossilised gastric pellets produced by routine emesis. Unfortunately, few reports of emetolites have been made; those specimens reported to date are reviewed. Various hypotheses may explain this negative result, the strongest being a collection bias. Because paleontologists do not expect to find them, emetolites may go unrecognised or uncollected or could be destroyed inadvertently during preparation. Emetolites would offer a valuable fossil record, and thus they warrant consideration by field paleontologists and preparators. A greater awareness of their probable characteristics may lead us to discover that they are more abundant than has been assumed.

(Photo: leighadactyl)

Can you guess the author? Hint: he has been featured on this blog many times and, while deeply involved in paleontology, is better known these days for cooking, nuclear power, and trying to cool the earth.

Much of what paleontologists have learned about dinosaurs—especially about how they lived—has been deduced from evidence other than just the fossilized bones they have found. Big breakthroughs in the field arrived, for example, after researchers learned how to spot dinosaur footprints, dinosaur eggs, imprints of dinosaur feathers, and even fossilize dinosaur scat.

In a new paper, Nathan Myhrvold suggests there may be yet another treasure trove of information to be unearthed in the form of dinosaur pellets—the chewed-up bones, teeth, and other indigestible bits of prey that predators of many kinds regurgitate after big meals. Most predatory birds alive today, from owls to hawks, routinely vomit up gastric pellets; there is some evidence that crocodiles do as well. In his paper, Myhrvold surveys reports on previously discovered fossils that might be gastric pellets from predatory dinosaurs, and he suggests what characteristics paleontologists should look for when they are out in the field. It may be, he speculates, that lots of fossilized pellets have been seen already but not recognized for what they are.